Eels

Their body is as bigger around than my arm

Babylon Wall

No, it is not trying to bite, that is how they breath

At Coral Garden.  Some think this is a honeycomb eel, but does not look like the ones I have seen

They are very shy, and usually hide back in the sand when approached

I apologize the focus is not sharp enough.

Many cleaner shrimp climbing on and around the eel, eating the dead skin and parasites on the eel,

Juvenile.  The body turns blue as an adult, the yellow ribbon remains